There can be a number of reasons for dead car batteries, ranging from something serious such as a short in the electrical wiring to simpler causes such as failing to plug in the car during winter and leaving the lights on overnight. Car owners need the services of a skilled and experienced mechanic for serious problems, but dead car batteries can be charged with the right equipment.
You will need jumper cables and a second car with a functional battery. Jumper cables can be found in stores that sell hardware and automotive parts, recognizable using their two red and two black clamps. However, finding a second car can sometimes mean counting on the kindness of strangers.
Since the process can be dangerous, be sure to consult your owner's manual and take the proper precautions while following these steps on how to jump-start a car:
- Make sure the car battery is dead rather than in need of replacement: see if the dashboard can light up, if the headlights turn on, and inspect the car battery for visible signs of damage. In most cars, the car battery is found in the front of the vehicle, though other potential locations include both the trunk and behind the engine. Bear in mind that none of these methods are perfect, since a dead car battery can still provide lighting, while not all damage can be discerned with a glance.
- Once you're confident that the car battery is dead, it's time to jump-start it. Park the second car close for convenient access and make sure that the cars are not in direct contact. Be sure to turn off both cars before attempting to jump-start the disabled car as leaving the cars running could cause damage to vehicle electrical systems.
- The positive terminal on the car battery should be marked with a '+' sign, while the negative terminal should have a '-' sign. Similarly, the positive terminal should be connected to a red cable, while the negative terminal should be connected to a black cable.
- Connect the red clamp of the jumper cable to the positive terminal on the dead car battery, and then connect the other end of the red clamp to the positive terminal on the good car battery. Don't connect to the charged battery first, as it can spark!
- Next connect the black clamp of the jumper cable to the negative terminal on the good car battery. Connect the other end to a non-moving part of the dead car's engine where you can see bare metal (this is a ground). Only as a last resort should you connect the battery to the negative (-) terminal of the dead battery as this could cause an explosion. Be careful not to touch the clamps to anything once the jumper cables have been connected to the car batteries, since that can lead to serious electrical problems.
- Before attempting to jump-start the disabled car, make sure that the cables are not dangling inside the compartments of either car so as to catch in any moving parts.
- Start the second car with the functional car battery. Let it run for a couple of minutes and then rev its engine a little (don't race it; rev it a little above idle) to charge the dead car battery.
- Attempt to start the car with the dead car battery. If the first attempt fails, check the electrical connection before making a second attempt to jump-start the disabled car. Bear in mind that repeated failures mean that the dead car battery needs to be replaced.
Since each car is different, car owners should consult their manuals of speak with a trained technician in case of questions. Furthermore, being able to jump-start the car does not mean that its car battery is in good condition, since some car batteries can be charged initially but cannot hold a charge. Visit our service department if you have any doubt of your battery's condition and we can test it for you and replace it if needed.